The S. mutans genes coding for glucosyltransferase, fructosyltransferase, invertases, the sucrose trasport system and glucan receptors will be cloned in E. coli utilizing the recombinant DNA technique. The transformed clones will be used to investigate the role of the gene products in the cariogenic properties of S. mutans. Transformed minicells of E. coli containing the genes for glucosyltransferase will be utilized to futher characterize the isoenzymes of this activity and to examine the regulation of the synthesis and secretion of these exoenzymes. Mutants of these clones defective in phospholipid biosynthesis will be sought in order to invesigate the role of phospholipid-exoenzyme interaction in the secretory process. It will also be of interest to examine the interactions of glucosyltransferases with lipoteichoic acid. The isolation of clones carrying either the extracellular or intracellualr invertases will be utilized to examine the relationship between these two activities. Amplifiable clones containing the glucan receptors will be utilized to isolate and characterize these receptors. Purified cell surface components of S. mutans will be incorporated into liposomes in order to investigate the role of these molecules in attachment to tooth surfaces. Liposome-glucosyltransferase-glucan receptor complexes will also be constructed to examine the role of these receptors in sucrose-dependent colonization. The sucrose transport proteins of S. mutans cloned in E. coli will be isolated and incorporated into liposomes in order to examine the mechanism of sucrose transport.